Components of an integrated circuit (IC) can be affected by interference from signals on the IC. For example, in a radio transceiver IC there can especially be interference from the clock signals that are used to provide for synchronisation in the circuit. One approach to reducing the effect of this interference is to select the clock frequency carefully to reduce the effect of its interference, but it is often difficult to select a suitable frequency because of the range of electrical components with which the frequency might interfere. Another approach is to shield the conductive lines that carry the clock signal, but this is often impractical, and conflicts with the requirements to reduce the size of the IC. A further approach is to route the conductive lines that carry the clock signal in such a way that the interfering effect that they have on other components is reduced. This latter approach is accompanied by two difficulties. First, the effect of a particular route on interference is difficult to predict simply from a circuit design, since it depends on many properties of the IC and the material of which it is made. This means that in order to find a successful routing it is often necessary to build a test version of the IC with a routing that might work, test the IC, and then feed variations to the design back into subsequent test IC designs. This iterative process is often undesirable because of the high costs of configuring a fabrication plant to produce a particular IC design and the requirement to reduce the time taken to bring new IC designs to market. Another problem with this approach is that many ICs are so congested that it is very difficult to find one route that does not cause interference. More specifically, moving a clock line away from one component to reduce interference normally requires moving it towards another component where interference is consequently increased.
The aforementioned considerations are not limited to clock lines on ICs. Clock lines are a particular problem because they often need to run to a range of locations on an IC, but interference can come from other sources on other lines. In addition to ICs, similar considerations apply on circuit boards and within device assemblies as a whole.
Accordingly, there exists a need to reduce interference from sources such as clock lines in devices such as ICs.